Tube Preamps?

For a few years, I have been "bottom feeding" with a NAD 1135 preamp. Even though it's old, it has served me well. Now, however, I am thinking seriously about going into the used tube preamp market.

I am looking for a tube preamplifier that would sound good with my current gear, which consists of: B&K 140 amp, Vandersteen 2C speakers, a Music Hall TT, a Denon CD player, and ~10,000 LPs. I have been considering an ARC SP-9, a big old Macintosh, etc.

A couple of things to consider. Most importantly what is the input impedance of your amp? If it is 10K which is typical in a lot of solid state you have to be careful as most pre-amps, especially the simpler less expensive variety, and a lot of the pricey stuff as well, have output impedances of 3500 ohms which does not predict a good match with a 10K ohm amp. If the amp is 50K or 100K it is usually not an issue. For example my pre-amp has an out put impedance of 600 ohms and ARC recommends amps with impedances of 20K. Could be you would not hear the difference. Could be. But at 3500 ohms you would.

You present equipment suggests to me that you are looking for a modest priced used pre-amp with a phono section. A good one (and there are many others), if the impedance issue doesn't exist, would be a Primaluna Three w/added MM phono stage. Its tone is easily influenced with changes in the tubes, it is rugged and dependable, on the warm side of neutral. It is very quiet as well. But it does have an output impedance of 3500 ohms so be warned. They are often available for about 1K and are easy to resell. If the idea appeals but you can only find one without the phono stage you can obtain and install one of these from a dealer. FWIW, it is especially nice when matched with the Primaluna 5 amp with KT88 tubes.

Hope that helps a bit.
My only idea is this: At one time I had a NAD 304 as my preamp, and I went with a Quicksilver Linestage using 12AU7 tubes (it was a very early model, SN 0005). That single change was as big a step up as I've taken since I've been doing this hobby.
Not a recommendation for a Quicksilver, but a recommendation to follow through on your hunch.
The amp I have is an old B&K ST140. Sterophile (favorably) reviewed the amp way back when, and put it on the bench before listening. They rated the input impedance at 24.3k ohms. Since I am not much of an EE, I'm not sure if that's good/bad/something to watch.
Another one you may want to look at is a Sonic Frontiers SFL-1. It's not made any more, but if you find a good used one, I can't see you not being happy with it. I had one when it was still in production and was very happy with it. Sounded like a much more expensive unit.

Also, I just remembered that I had a b&k amp (don't remember the model) at the time and the results were very good.
How about the Van Alstine T8 posted here on Agon?
Audible Illusions 3A would be a nice upgrade. It's a great preamp used. All the best...
I am not a big fan of the SP-9. It is a hybrid using old FET technology. BTW there are 3 versions of the preamp with the MKIII version being the best of the three. They have crosstalk issues. If you're looking for a preamp with a phono stage, look at a used SP-16. Much better sounding preamp.
You can probably get a Rogue
for a good price. Cary SLP98 is a pretty nice preamp. You haven't stated how much you want top spend?
My opinion on Audio Research is similar to hifigeek1's comment. AR is all over the place with their preamps. Some of them sound great while others don't. They aren't consistent from model to model. I'm not saying to avoid them, but I would never consider buying one blind. Highly recommend you demo first.
I second the Audible Illusions 3A recommendation or the Audible Illusions L-1 if you have an outboard phono preamp. Even though both preamps share the same linestage, I prefer the master gain control with one volume on the AI L-1 rather than two volume controls on the AL 3A. You can expect very good dynamics and transparency with both not to mention top notch sound quality.

The other tube preamp I like after trying many is the VTL 2.5. Try and find one with a tube phono circuit installed.
If you want the classic/warm tube sound, a Conrad Johnson PV-5 or and ARC SP3 would be great. Both ARC and CJ will still support/update these products with their top-flite service.

A friend of mine used a VTL 2.5 with 2C's (he recently moved on to the 3A sigs but kept the VTL in the system).

I would also recommend looking into Quicksilver's line of products. You can usually find their linestages for well under $1000, and I've seen several of their full function preamps go for right around $1000. You could also consider a modified Dynaco PAS-3 from tubes4hifi (VTA).
DO you have a price range you are wanting to stay around?

The AI3 has been on my short list for years...

I am wavering on how much to spend. My ultimate goal is to be able to play my LPs, and to port them all over to my PC as lossless digital files.

I now have a NAD 1155 preamp, and wonder how much of a difference it would make by saving up for a really good preamp.

Should I spend $100 or $1000? I'm unsure.

I read all the reviews in Abso!ute Sound, and Stereophile. The models did seem to vary quite a bit. The SP-9 seems to have attained "classic" status, however. As did the LP-12, Quad 63s, etc.

Classic status should go to the ARC SP-8MK2 preamp. The ARC
preamps are great builds and their service is outstanding.
To me the Audilbe Illusions 3A used is considered one of the best full function preamps ever made. Of course waiting for service could be a while. But their failure rate is a very low percentage. All the best...
A good one - from sound and reliability - is a used Lamm LL2
Licoricepizza2, Re impedance matching I mentioned earlier, 24.3K and a pre-amp with 3500 output impedance might integrate well especially if the 'tightest' bass is not an objective, nor a bit of bass bloom at times is objectionable to you. That is what you might expect from your system I think. BTW I used to own an identical amp, a nice amp especially tonally speaking.

Keeping your costs down you might consider pre-amps that come up time to time which can do the job you want consistent with your other components. I used (and still have actually) a Magus pre-amp which I used as a back up to my ARC SP10. When these appear they usually sell between $500 and $750.

Re some of the above recommendations, I think the Conrad Johnson PV 5 is excellent and easy to use. I also think the AI 3A is as well but, unfortunately doesn't have great flexibility tube wise to change it tone if you want to, but you also have to deal with two volume controls, one per channel. Too bad they didn't use these volume controls as gain controls with a master volume control (as the Magus does), but for me the ARC SP82 (revision 7 if possible) would be an outstanding choice if you can afford one that is in top condition. The ARC SP 9 looks cool but sounds sterile and I wouldn't own one at any price.

Hope that helps a bit.
I would say $1,000 and below.
I'm going to look around for a decent CJ5. I'm definitely not interested in something that will make my ears bleed. I went that route decades ago. I'm still recovering.